One existing type of strain gauge is the electrical resistance foil strain gauge. For uniaxial strain these typically require bridge completion and precision conditioning equipment. Further, electrical resistance foil strain gauges generally use higher power levels than is desirable and their use involves careful work by personnel owing to their low output signal levels.
Another broad type of gauge is the “clip” gauge, which incorporate a full bridge. However, clip gauges generally do not have a low profile, and are unsuitable for permanent installation. Further, they also consume considerable power and are relatively expensive.
Columbia Research Laboratories, Inc. produces a full bridge product using metallic gauges, but this does not have as high a sensitivity as is desirable in many applications.
Thus, existing strain gauges have relatively high power requirements, generally require bridge completion, and have low output signal levels.